DETERMINATION OF THE AGE OF FOSSIL -
- Radioactive clock (Boltwood-1907) - Half life of uranium is 4.5 billion years.
- This means half of total uranium disintegrates into lead in 4.5 billion years 235u decays to 206pb. By calculating the amount of lead in a rock, one can approximately estimate the age of fossil.
- Radio carbon method - (W.E Libby - 1950).
- Potassium argon method - Potassium is a common element found in al rocks.